Discovery of an OH (1720 MHz) Maser in the Large Magellanic Cloud

Abstract

We report the first study of OH (1720 MHz) masers in the LMC in order to probe regions where supernova remnants interact with adjacent molecular clouds. Using the Australia Telescope Compact Array, we observed four sources in the LMC and detected a single OH (1720 MHz) maser with a flux density of 377 mJy toward 30 Dor. No main line emission at 1665 or 1667 MHz was detected. The observed OH (1720 MHz) maser emission from 30 Dor shows characteristics similar to the well-known collisionally pumped supernova remnant masers found in the Galaxy, though 30 Dor is known as a star-forming region. It is possible that shocks driven by a nearby supernova remnant or by strong stellar winds from young stars are responsible for production of OH (1720 MHz) maser in 30 Dor. Future studies are required to distinguish between collisional and radiative pumping mechanisms for the 30 Dor OH (1720 MHz) maser.